TST: enable Python 3.5 tests

Author: matthew-brett

.travis.yml

@@ -26,6 +26,7 @@ python:
     - 3.2
     - 3.3
     - 3.4
+    - 3.5
 matrix:
   include:
     - python: 2.7
@@ -45,6 +46,7 @@ matrix:
         - DOC_DOC_TEST=1
 before_install:
     - virtualenv --python=python venv
+    - pip install -U pip  # upgrade to latest pip to find 3.5 wheels
     - source venv/bin/activate
     - python --version # just to check
     - pip install nose # always